In a compressor, e.g. a centrifugal compressor, one or more impellers may be used to compress a fluid (e.g. gaseous refrigerant). Typically, the one or more impellers are mounted on a shaft, which is driven by a motor. The shaft can be supported by one or more bearings, which can be configured to withstand axial and radial forces in operation. Some bearings require lubrication in operation.